The present invention relates to a new and distinct variety of Japanese type plum (Prunus salicina Lindl.) tree which is named xe2x80x98Gulfrosexe2x80x99 and, more particularly to a plum tree which is adapted to central and north Florida winter climate with annual and heavy crops which ripen in the mid- to late May in the adapted area. Contrast is made to xe2x80x98Gulfrubyxe2x80x99 (unpatented) plum for reliable description and contrast. This new variety is a promising candidate for commercial success in Florida because it bears fruit ripening in spring when few plums are available from the U.S.
This plum tree originated from the University of Florida stone fruit breeding programs at Gainesville from an open pollination of xe2x80x98Gulfrubyxe2x80x99 (unpatented) plum, and hereinafter will be referred to varietally as xe2x80x98Gulfrosexe2x80x99. The present variety was selected in 1995, and has been tested as Fla. 95-4 plum. xe2x80x98Gulfrosexe2x80x99 has been asexually propagated by budding onto xe2x80x98Flordaguardxe2x80x99 (unpatented) peach rootstock in an experimental orchard at Gainesville for 2 succeeding generations, which shows that characteristics of the tree are established and uniformly transmitted. xe2x80x98Flordaguardxe2x80x99 does not impart any known characteristics to the scion variety different than other root-knot nematode resistant peach rootstocks.
This new and distinct variety of plum tree is large, vigorous, and semi-spreading in growth. It has an estimated chilling requirement of 275 chill units, but appears to have a high heat requirement for breaking dormancy in that xe2x80x98Gulfrosexe2x80x99 trees bloom before the earliest standard Japanese varieties at Gainesville, but with or after the same standard Japanese varieties in north Florida locations. Winter temperatures of 14xc2x0 F. in Florida have not damaged wood or flower and leaf buds. xe2x80x98Gulfrosexe2x80x99 is adapted to the winters of north central and north Florida, overlapping the second half of the flowering period in xe2x80x98Gulfrubyxe2x80x99, xe2x80x98Gulfbeautyxe2x80x99 (U.S. Plant Pat. No. 11,224), and xe2x80x98Gulfblazexe2x80x99 (U.S. Plant Pat. No. 10,873) plums, and xe2x80x98Gulfrosexe2x80x99 is cross pollinated with pollen from each of them. None of these plums are self fertile and all require cross pollination for fruiting. xe2x80x98Gulfrosexe2x80x99 is a regular and productive bearer of medium size, firm, semi-freestone fruit with good eating quality and a slightly tart skin. The fruit is further characterized by having deep red skin, firm, blood flesh, hanging on the tree 10 days after maturity (shipping ripe) and ripening 7 to 10 days after xe2x80x98Gulfrubyxe2x80x99. Fruit set is very high and fruit thinning may be required to prevent limb breakage and size fruit properly. The new variety is distinguished from xe2x80x98Gulfrubyxe2x80x99 in having blood flesh, later ripening fruit and a higher degree of resistance in leaves, twigs, and fruit to bacterial leaf spot. Fruit of xe2x80x98Gulfrosexe2x80x99 are highly resistant to sun scald (xe2x80x98Gulfrubyxe2x80x99 is highly susceptible), concentric skin cracks, and split stones. Leaves have moderate resistance to leaf scald.